Mobile track tamper

ABSTRACT

A track tamping machine having a plurality of ballast tamping heads mounted on a carriage thereof. At least one of the tamping machine heads is slidably mounted longitudinally of the carriage and the tamping heads are spaced longitudinally with respect to the track on the carriage. The slidably mounted tamping head is capable of performing a tamping operation whilst the carriage is moving along the track.

United States Patent I 91- Stewart 1 Jan. 16, 1973 [54] MOBILE TRACK TAMPER [75] Inventor:

[73] Assignee: Tamper Inc., West Columbia, SC.

22 Filed: July 8,1970 21] App1.No.:53,076

-[52] US. Cl. ..104/12 [51] Int. Cl. .;.,..E01b 27/16 [58] Field of Search ..104/12, 12 B,7R

[56] References Cited UNITED STATES PATENTS 3,504,635 4/1970 Stewart et al ..104/12 3,380,395 4/1968 Plasser et al 2,734,463 2/1956 Hursh et al. ..104/12 John Kenneth Stewart, Columbia,

FOREIGN PATENTS QRAPPLICATIONS 1,154,311 6/1919 GreatBritain ..104/12 793,377 4/1958 Great Britain ..104/12 Primary Examiner-Drayton E. Hoffman Assistant ExaminerRichard A. Ber'tsch Attorney-Smart & Biggar I [57] ABSTRACT A track tamping machine having a plurality of ballast tamping heads mounted on a carriagethereof. At least one of the tamping machine heads is slidably mounted longitudinally of the carriage and the tamping heads are spaced longitudinally with respect to the track on the carriage. The slidably mounted tamping head is capable of performing a tamping operation whilst the carriage is moving along the track,

1 Claim, 1 Drawing Figure PATENTEUJAN 1 6 1975 I'll.

ATTORNEYS.

MOBILE TRACK TAMPER BACKGROUND OF THE INVENTION The present invention relates to a railway track ballast tamping machine. In particular the present invention relates to a machine which may be operated at an increased speed with regard to conventional tamping machines and which, in one embodiment, may be adapted for continuous operational movement along the track.

Conventional tamping machines, such as for example the one disclosed in Canadian Pat. No. 646,048, are provided with tamping heads which tamp a single tie at one time. The tamping machine remains stationary at the tie being tamped until the tamping operation of that tie is completed. Then the machine moves on to the next tie to be tamped and the tamping cycle is repeated. Thus the speed of operation of the machine is governed by the speed of the tamping cycle.

Attempts have been made to increase the production rate of tamping machines by doubling or even tripling a number of tamping heads on the machine, see for example Swiss Pat. No. 444,207, but with all the suggestions to date it is necessary to wait until all the tamping systems on the machine carriage have tamped their respective ties before moving the carriage along. Thus the rate of progress of the machine along the track is limited by the speed of the slowest tamping head operation.

The present invention provides a track tamper machine for instance of the type seen in the aforementioned Canadian Pat. No. 646,048, which can move at substantially greater speeds and which in one embodiment is adapted for continuous operation along the track.

SUMMARY OF THE INVENTION According to the present invention there is provided a track tamping machine which comprises a carriage movable along the track, a plurality of ballast tamping heads mounted on said carriage, at least one of which tamping heads is slidably mounted longitudinally of the carriage, said tamping heads being, spaced longitudinally with respect to the track, on said carriage, characterized in that said at least one slidably mounted tamping head is capable of performing a tamping operation during carriage movement. Means may be provided for downfeed into the ballast of a tamping head on location thereof above a tie spaced from the tie previously tamped by that head by a number of ties equal to the number of tamping heads on the carriage.

The slidably mounted tamping head or heads, preferably is or are, the rearward head, or heads, on the carriage. By making it, or them, capable of operation during carriage movement, it is not necessary as it would be in an arrangement where the heads are merely duplicated, or triplicated, to wait until all the heads on the carriage have tamped their respective ties before moving the carriage on. It is only necessary to wait until the foremost tamping head has completed its tamping operation before moving on, for if the rear tamping heads are still tamping when the foremost one has completed its tamping, on moving the carriage along the track, those heads still tamping merely slide rearwardly along the carriage and continue their tamping operation until complete. Thereafter the tamping heads are returned forwardly on the carriage and proceed to tamp the selected next tie. In the above assembly the tamping heads may be suitably biased forwardly on the carriage.

In the preferred embodiment according to the present invention the tamping machine itself and each of its slidably mounted tamping heads is provided with a sensing means arranged to stop the forward motion of machine or head and downfeed the tamping heads when each tamping head is over its correct tie. Such a sensing means may suitably comprise a downwardly depending spring-loaded position sensing finger such as is disclosed in the aforesaid Canadian Pat. No. 646,048 which is set so as to actuate a sequencing control circuit to stop the machine and downfeed the fixed tamping head after the sensing finger has contacted and passed over the preselected number of ties. Each slidable tamping head has a similar tie sensing finger which actuates an individual sequencing control circuit for each tamping head to downfeed that head when it is correctly positioned over its tie. Alternatively, the

machine and each tamping head could be provided with a positioning means such as shown in US. Pat. No. 3,504,635. In that device a track travelling vehicle with a fixed leading tamping head mounted on the chassis of the vehicle and a second tamping head mounted for longitudinal movement on the chassis relative to the first tamping head under the action of its own motor means has a first control means operable in response to the detection of a first index reference to a first tie to be tamped to control the forward travel of the vehicle so as to position the leading tamping head over the first tie and a second control means movable with said second tamping head responsive to the detection of a second index reference to a second tie to be tamped and operable, if the first control means has not already operated, to actuate the motor means to drive the second tamping head rearwardly of said chassis as the vehicle moves forward to lock the-second tamping head on to said second tie; said first control means operating, if said second control means has not alreadyoperated, to stop the forward travel of the vehicle and to actuate said motor means to drive the second tamping head forwardly of said chassis to hunt'for said second tie.

In one embodiment according to the present invention the forward tamping head is itself movable and thus all of the tamping heads on the machine are slidably mounted for longitudinal movement on the vehicle carriage. By means of this embodiment, it is possible to continuously operate the tamping assembly along the track, as due to the longitudinal slidably mounting of each tamping head it is not necessary to stop the vehicle for any particular tamping head on the carriage.

In a further preferred embodiment means are provided on the vehicle for continuously raising the track, and additional means may also be provided for continuously aligning the track so that a surfacing and aligning operation may be conducted and the track tamped in its corrected position without the vehicle having to stop at all.

DESCRIPTION OF THE DRAWINGS The following is a description by way of example of one embodiment of the present invention, reference being had to the accompanying drawing in which the essential parts only are shown.

DESCRIPTION OF PREFERRED EMBODIMENTS A motor driven track tamping vehicle is provided with a chassis 11 on which a fixed tamping head 12 is mounted near the front of the chassis 11. The tamping head 12 is a conventional vibrating tamping head which is mounted on a frame 13 so as to be capable of being lowered into the ballast about a tie 14 to squeeze the ballast with the vibrating tools 16 and thereafter to be withdrawn and raised out of the ballast. A second tamping head 17 is mounted on a frame 18 which is provided with wheels 19 for sliding in guides 20 longitudinally of the chassis 11. The tamping head 17 is normally biased by a biasing means, such as a spring or a hydraulic piston and cylinder arrangement generally indicated at 21, against a positioning stop 22 spaced from the leading tamping head such that the head 17 is correctly spaced from the fixed head to a tamp a tie not previously tamped by the head 12. Each tamping head 12 and 17 is provided with its own conventional sequencing circuit which controls the lowering of the vibrating tamping heads into the ballast, the squeezing of the ballast about a tie and the outfeeding and upfeeding of the vibrating tamping heads from the ballast. Diagrammatically indicated at 23 is a tie indexer which may be of any known type. For example, it may be of the type seen in Canadian Pat. No. 646,048. When this tie indexer has passed over the requisite number of ties, it actuates a control circuit as is well known in the art, to stop the vehicle and to initiate the operational sequencing of the tamping head 12. The rear tamping head 17 is similarly provided with a tie indexer 25 connected to the moving frame 18. In the drawings for the sake of clarity the indexer 25 is shown reaching well forward of the head 17 but of course in actual fact it will be located in the center of the head 17 over the tie to be tamped. Again when the requisite number of ties have been passed the tie indexer 25 operates to release the biasing means 21 which maintains the head 17 against its positioning stop 22 and start the tamping cycle of the tamping head 17. Thus, because of the independent control circuits of the tamping heads, if the tamping head 12 completes its tamping operation and rises out from the ballast to trip a switch and start the forward motion of the vehicle 10 before the tamping head 17 has completed its tamping operation, the vehicle will simply move forward and the tamping head 17 will slide on its frame 18 on rollers 19 in guideways 20 until the tamping cycle is completed and the tamping heads 17 are raised out of the ballast. On reaching the tamping head reaching its upper-most position, the biasing means 21 are again actuated and the tamping head 17 is driven forwardly on the chassis l 1 until it encounters stop 22 at which stage the head 17 is correctly spaced from the front tamping head 12 for the next tamping cycle.

In an alternative construction, a positive displacement pump P is connected to the rear wheel so that if the tamping cycle of the rear tamping head 17 is not completed when the front tamping head 12 is returned to its upper-most position and the vehicle has started to move, the pump P operates a hydraulic motor to displace the tamping head 17 rearwardly on the chassis l1 at the same rate as the forward motion of the vehicle, so that the tamping head 17 will be maintained over the tie being tamped. On completion of tamping the head 17 is returned to the stop 22.

It is not at all infrequent to meet a section of track in which the tie spacing is so irregular that to move the rear head fully forward against its stop 22 would cause the head 17 to be mispositioned. Under such circumstances, the head 17 can be started initially at a position nearer the rear of the vehicle and after tamping, moved forward by the piston 21 as before. However, in this mode of operation the forward travel of the piston 21 is terminated by a command signal generated when the indexer 21 has counted the requisite number of ties, whereupon the head 17 is lowered into the ballast and the operation proceeds as before. The position sensing and controlling arrangement such as described earlier with reference to US. Pat. No. 3,504,635 is particularly useful as a control medium in a situation where irregular tie spacing is likely to be encountered.

It will be understood of course that whilst only one rear tamping head has been shown in the drawing, the invention, as has been stated earlier, contemplates the use of several tamping heads each of which would have its own independently operated sequencing circuit, controlled from its own tie indexer or like controller, to enable it to operate on a tamping cycle independently of the other tamping heads.

Furthermore, the fixed head 12 could be mounted to similarly slide in guides under the control of its own indexer. The carriage may also be provided with means for lifting the track (not shown), for example magnetic lifters, so that the track may be lifted to the desired height before tamping i performed. If such a jacking system is incorporated with the tamping machine, an infra-red radiation surveying device of conventional form could advantageously be used. The receiver R for such a device is illustrated in the figure. Similarly, also a conventional track aligning device could be provided.

Depending upon the number of tamping systems mounted on the machine, the sensing switches will have to be programmed to count a corresponding number of ties before actuating the tamping cycle of the associated tamping head.

What I claim as my invention is:

1. A track tamping machine comprising a carriage movable along the track, a plurality of ballast tamping heads mounted on said carriage, said tamping heads being spaced longitudinally with respect to the track, an independent control for the independent operation of the tamping cycle of each head; position adjustment means to slidably mount one of the tamping heads for longitudinal movement on the carriage and operable on the commencement of carriage movement to drive said slidable. tamping head, when said slidable tamping head is performing a tamping operation in the ballast during carriage movement along the track, rearwardly relative to said carriage and at substantially the same rate of movement as said carriage movement and including means, operable on completion of each tamping operation, to move said slidable tamping head forwardly on said carriage; each independent control including a track engaging sensing means to actuate the tamping cycle of the associated tamping head when that tamping head is positioned over a correct tie to be tamped. 

1. A track tamping machine comprising a carriage movable along the track, a plurality of ballast tamping heads mounted on said carriage, said tamping heads being spaced longitudinally with respect to the track, an independent control for the independent operation of the tamping cycle of each head; position adjustment means to slidably mount one of the tamping heads for longitudinal movement on the carriage and operable on the commencement of carriage movement to drive said slidable tamping head, when said slidable tamping head is performing a tamping operation in the ballast during carriage movement along the track, rearwardly relative to said carriage and at substantially the same rate of movement as said carriage movement and including means, operable on completion of each tamping operation, to move said slidable tamping head forwardly on said carriage; each independent control including a track engaging sensing means to actuate the tamping cycle of the associated tamping head when that tamping head is positioned over a correct tie to be tamped. 